I agree that the demand before 1960 doesn't work in v2.13, but we do have a solution for that in v2.14.
I have done a lot of research on the airliner classes and how they were perceived in certain eras or when they were introduced.
But please, correct me if I'm wrong!
(preferably with sources)
I don't think we need a separate class apart from First class before 1959. (Economy gets introduced sometime in '59)
Flying before the introduction of Economy (Coach Class back in the day), flying was only for the wealthy.
Sure, the class probably wasn't called First Class as there was no second class, but I think it depicts best for who it was meant.
If you weren't rich, you probably travelled second class by rail or ship.
First class back in the day is not even close to the comfort of what we call First Class today.
But the price is why I'd call it First Class: a trip from New York to California costed $3900 in 1930 in today's money.
The bad seats in those planes will lower the demand or force your prices down, which is good in my opinion. (remember the demand issue will be solved for 2.14)
But if you do have an example of an actual 'low cost' flight before the introduction of Economy Class, let me know.
I rethink the implementation then.